Both cutaneous and visceral leishmaniasis are endemic in Ethiopia. Epidemiological and immunological studies of localised and diffuse cutaneous leishmaniasis during the past eight years have revealed that the differences between the two types are due to host immunological response variations rather than to differences in the etiologic agents. The rock-hyrax has also been found to be its natural reservoir host. There is very little known about visceral leishmaniasis (kala-azar) as it occurs in Ethiopia. The epidemiology (including vectors and reservoir hosts), pathology, and immunology of this disease is now under investigation. Speculations based on studies done in the Sudan, Kenya, and other parts of the world lead us to believe that the Ethiopian variety of kala-azar, as in the case of oriental sore, may have unique and varied epidemiological and immunological patterns. The experimental methods to be followed will be essentially those reported previously (see our publications). Epidemiological studies on kala-azar will be conducted in known endemic areas, including Setit Humera (northwestern Ethiopia extengind to the Red Sea), and Gemu Gofa (southwestern, Ethio-Kenyan border). These are all important public health and agricultural development areas; the study will therefore have a direct and immediate use for Ethiopia.